Can I hear electromagnetic radiation coming from a pulsar star? Or can I hear it if I stand outside it?
Sound as you hear it is waves of pressure differences in the air, which is interpreted by your ear as sound. So no, you cannot directly hear electromagnetic radiation (EMR). You could, however, take the EMR and convert it into sound waves in the audible range, which you could listen to.
This was done in 1990 for Jupiter by Voyager as it passed Jupiter. It converted x-rays to audible sound. The video says that sound can exist at EMR, but I would have to disagree on that point. Anything that behaves like a wave can be turned into sound, but it doesn't exist as sound in the original form.
Electromagnetic radiation is light. Like any other star, you can see the radiation from a pulsar if it is not too far away or too dim.
Pulsars and other stars do produce very loud sound. We do not hear it because there is vacuum between stars and us. Sound does not travel through a vacuum. Also stars are so very far away that we wouldn't hear it anyway.